In the past, internal combustion engines have conventionally been made of metal, usually cast iron. Cast iron engines are effective, but they are generally noisy, heavy and are becoming increasingly expensive and time consuming to produce. Generally, the weight and bulk of an engine substantially affects the overall performance, e.g., fuel efficiency of the car, truck, boat, airplane or other vehicle or machine which it powers. Corrosion is a major problem in marine and industrial engines as well. Moreover high fixed asset costs to build new engine facilities are at this time a considerable problem. Costs to operate and maintain foundries have sky-rocketed. Sand and permanent mold casting technology has not kept up with the reduced manufacturing times which engine manufacturers believe are necessary to remain competitive in the world-wide marketplace.
In the search for ways to improve production economics and to reduce engine noise and weight and to increase fuel efficiency it has been proposed to construct engines and engine parts from materials of a lighter weight than the heavy metal, e.g., cast iron, conventionally used in the automotive art. In my prior U.S. Pat. Nos. 4,430,906; 4,430,969; 4,430,970; 4,432,311; 4,432,925; 4,433,652; 4,433,964; 4,440,069; 4,453,505; 4,458,555, for example, it has been proposed to manufacture various engine parts, such as wrist pins, rocker arms, tappets, piston rings, valve spring retainers, push rods, timing gears, valves, connecting rods and the like, from certain amide-imide polymeric materials which have been found to be particularly suitable for such purposes. Linsenmann, U.S. Pat. No. 4,186,696 discloses a push rod formed from resin reinforced with fibers, such as glass fibers. Driver, U.S. Pat. No. 4,306,489 describes a composite piston formed from a fiber-reinforced epoxy resin and having an aluminum cap portion. The engine head and block, however, have presented more of a problem, although some steps in this direction have been taken. The patent art, for example, includes Hartsock, U.S. Pat. No. 4,508,066 which shows a head assembly comprising a cast ceramic body. Rynbrandt, U.S. Pat. No. 4,398,527 discloses the coating of the manifold and combustion surfaces of a conventional internal combustion engine with a resinous composition comprising a polyimide or polyamide resin. Formia, U.S. Pat. No. 4,436,066 describes a cylinder head formed from aluminum, and an aluminum cylinder head construction is also disclosed in Hayashi et al, U.S. Pat. No. 4,614,172. Tsuchiya et al, U.S. Pat. No. 4,515,112 discloses an aluminum alloy cylinder block and Kubozuka, U.S. Pat. No. 4,446,827 discloses a cylinder block having a metallic body and side cover members formed from rubber or plastic which are present primarily for the purpose of suppressing noise and vibrations. Unfortunately, these non-cast iron engines or modified conventional engines have, in general, become as expensive and laborious to produce as the traditional engine and they tend to possess less than desired mechanical properties at operating temperatures.
It has been proposed by me to build plastic composite engine blocks and cylinder heads, such as described in "Popular Mechanics", September, 1982, p. 71, but these prior proposals have involved only very expensive materials and techniques entirely unsuited to mass production and cost effectiveness.
There has, therefore, been a continuing need and search for relatively lightweight cylinder heads and engine blocks for internal combustion engines which are effective and long-lasting in use, yet which can be mass produced economically and which attenuate noise.
It is, accordingly, an object of the present invention to provide an improved lightweight engine block and cylinder head construction for internal combustion engines.
It is a further object of the invention to provide an engine block and cylinder head construction of the character indicated which is formed from relatively-inexpensive resinous material.
It is a still further object of the invention to provide an effective engine block and cylinder head construction for internal combustion engines which is lightweight, is formed from relatively inexpensive resinous materials, and can be efficiently mass produced in a cost-effective manner.